bpo-43693: Add the MAKE_CELL opcode and interleave fast locals offsets. (gh-26396)

This moves logic out of the frame initialization code and into the compiler and eval loop.  Doing so simplifies the runtime code and allows us to optimize it better.

https://bugs.python.org/issue43693

3 files changed, 16 insertions, 6 deletions

diff --git a/Include/cpython/code.h b/Include/cpython/code.h
index c81f9f3..a338374 100644
--- a/Include/cpython/code.h
+++ b/Include/cpython/code.h
@@ -2,9 +2,16 @@
 #  error "this header file must not be included directly"
 #endif
 
+/* Each instruction in a code object is a fixed-width value,
+ * currently 2 bytes: 1-byte opcode + 1-byte oparg.  The EXTENDED_ARG
+ * opcode allows for larger values but the current limit is 3 uses
+ * of EXTENDED_ARG (see Python/wordcode_helpers.h), for a maximum
+ * 32-bit value.  This aligns with the note in Python/compile.c
+ * (compiler_addop_i_line) indicating that the max oparg value is
+ * 2**32 - 1, rather than INT_MAX.
+ */
+
 typedef uint16_t _Py_CODEUNIT;
-// Each oparg must fit in the second half of _Py_CODEUNIT, hence 8 bits.
-#define _Py_MAX_OPARG 255
 
 #ifdef WORDS_BIGENDIAN
 #  define _Py_OPCODE(word) ((word) >> 8)
diff --git a/Include/internal/pycore_frame.h b/Include/internal/pycore_frame.h
index 44f58fb..11c3a2c 100644
--- a/Include/internal/pycore_frame.h
+++ b/Include/internal/pycore_frame.h
@@ -32,6 +32,8 @@ _PyFrame_GetBuiltins(PyFrameObject *f)
 
 int _PyFrame_TakeLocals(PyFrameObject *f);
 
+PyAPI_FUNC(int) _PyFrame_OpAlreadyRan(PyFrameObject *f, int opcode, int oparg);
+
 #ifdef __cplusplus
 }
 #endif
diff --git a/Include/opcode.h b/Include/opcode.h
index a3a8b2a..c65e2f4 100644
--- a/Include/opcode.h
+++ b/Include/opcode.h
@@ -113,10 +113,11 @@ extern "C" {
 #define CALL_FUNCTION           131
 #define MAKE_FUNCTION           132
 #define BUILD_SLICE             133
-#define LOAD_CLOSURE            135
-#define LOAD_DEREF              136
-#define STORE_DEREF             137
-#define DELETE_DEREF            138
+#define MAKE_CELL               135
+#define LOAD_CLOSURE            136
+#define LOAD_DEREF              137
+#define STORE_DEREF             138
+#define DELETE_DEREF            139
 #define CALL_FUNCTION_KW        141
 #define CALL_FUNCTION_EX        142
 #define EXTENDED_ARG            144